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' Be it I'm-10m that I, WILLi'AM G. 'F Eiiouson,

a citizen theUnited' States, 1 {rest dent of Gardenflity, Nassau county, New

"ll orlc, have inuen'ted certain and Zus o'fu'l' Improvements n Processes of} Recovering Platinum Metals, of which the following is aspccification, I V

My invention relates to the recovery" of pl atinum and palladium from metal bearing suhstances and the subsequent separation of these metals from each other, My invention may be applied-to shines such as those ob tamed in. the electrolyt c refining 'Of'IIIGttLlS as, for insta11ce,"copper andfmaybe applied to those obtained in the manufacture of blue t'ltllOl and slinllar shines or mudst I may also apply my inventmn to thereco very of the platinum metals from flue dusts or the like,

the principal object of my invention being to extract these metals With a minimum" Waste of the precious metal and to acconm' plislii the extraction in an econoinical manner. lllectrolytm shines generallycontain gold, platinum, palladium, ,sllycr, copper,

selenium, telluriuin, arsenic, antimony, lead and silica in varying proportions and'some'e times contain also: traces ofbis'muth," nickel andiron. lnliny'prior ap li'c'a'tion o'for the treatment of electrolytic shmes, Serial No, 53,1 78, filed September 28, 19715, I describe a recess for the recoverybf the metal vanes from Sl'lIYlQS ofthis characten The 7 process described in said application consists essentially in subjecting slimes of" the character described to a roasting operation in the presence of a'sulfatizing agent until the sulfate of silver and copper are formed a such as suljiizric aei(l,'where by thcreis"proiv duced a second solid residue containingthe acid insoluhle constituents and solution "which contains sl'ibstantially allthe copper content of the fiiStsolid Tesidiiwavery small perc ntage of s'ili er and possibly -some inipurities. Tl ie addition ofhydrochloric acid or a suitablechlorid j ireci'pi ates the silver, with the rcsidile as an insoluble chloral.

The insoluble residue 7 contains essentially solubl 7 invention poss blyis chlorauric acid. This soluble gold compound 1s prcclpltated with ferrous Peseta e 9 1919;

i nast twas admin wart me.

15, platinum, palladium,Qtellurium. and traces oi't copper and lead. The concentrat'ioirol. the platinum metals in an in idue 'fOlll'lS the" firststep in my process further comprises the steps'of treating the residue W1th a chlorinating sub stance'suclras for instance aquarregiav A luhle gold compound is formed which sulfateiand :n'iay be'separated from the s0lut'ion. The insoluble silver is now recovered with a;solventsuch as sodium thiosulfate, as

described in my beforeinentioned prior apphcatmn;theresldue from the hypo treat n ent going to smelter. The acid solution remaining resulting from the chlorination contams practically all the platmum and palladium of the original shine, and also antimony, tellurium and traces of gold, lead and copper. The gold solution containing the"heforelnentioned substance I now satu "ratewith sulfur clioxid, as for instance by letting it bubble through the solution, T119311:

whilefheating the solution, either while saturat on is taking place or, afterward,

-toiateInperature of about 200 F, until tellurium' precipitates in appreciable quan- "tities; Alltheplatinum and palladium and gs'onie' cuprous chlorid still remaining are precipitated by this reducing agent. This precipitate is separated by filtration and 1 treated "with concentrated sulfuric acid and 90 heated'until theteinperature is obtained at whlch the acid fumes and all the tellurium compound present 1s decomposed, the volatile portionsthereof being expelled from the solution. Chlorin of the copper chlorid is also expelled from the solution by this heating operation. I then drop crystals of sodium nitrate into the hot liquid until practically all the telluriurn has become oxidized .andthe palladium dissolved. This solution isthen. diluted andfiltered. Ferrous sulfate then added and the palladium contained therein is precipitated, substantially free jl l'Oirl' telluriuin, or copper and containing" tracesoit' gold and platinum. The residue from the sulfuric acid treatment contains theplatinum. The residue containing the ,Lffillil andplatinmn isnow dissolved with aqua regia. The result of this treatment "produces a compound oi? gold and 'chlorin'f I and platinu'rnand chlorin, possibly the palladium and 'when Ispeak of nonprecio'us metals I mean all other metals not mentioned in this paragraph.

Various modifications may be made in the details without departing from the spirit and scope of the appended claims; the process described being merely for the purpose of illustrating an'exampleof I my invention.

I claim 1. The process of recovering platinum metals from electrolytic slimes whlch comprises subjecting such slimes to a sulfatizing roast, forming a concentrate of all the platinum metals contained therein and recovering said platinum metals substantially as and for the purpose described.

2. The process which com rises treatin an electrolytic slime to ren er substantiaquantities of the cop er and silver soluble separating the .solu e copper and silver from the residue containin substantially all the platinum metals of t e slime and recovering said platinum metals from the I residue.

In testimony'whereof I have hereunto set myhand.

WILLIAM C. FERGUSON. 

